Forty-eight emergency sirens located within 10 miles of the Palo Verde Nuclear Generating station are expected to sound off today as part of an annual federal requirement. They'll perform a practice blast at noon and at 12:30 p.m., authorities say.

Don't concern yourself with the horror those horns represent: The Department of Emergency Management says a real emergency is an "unlikely event."

The sirens are intended to get your attention in a real emergency and spur you to turn on your TV or radio. These days, that means look at your phone, which we assume may also give you an alert.

Image: maricopa.gov

Pete Weaver, the department's director, tells New Times that a November 8 news release by his agency deems the event "unlikely" because Palo Verde's the newest nuclear plant in the United States, using the "newest technology."

The plant became operational in 1988.

We're not losing sleep over a potential Palo Verde meltdown, meaning we must agree it's "unlikely." But news junkies like us can't help but think of worst-case scenarios this week as Japan moves into a delicate and possibly dangerous phase of the Fukushima cleanup operation. Also this week, Japanese officials told thousands of their citizens who lived within 12 miles of the plant to forget about going home -- ever.

Weaver tells us the Palo Verde sirens were placed within 10 miles of the plant, as opposed to say, 12, or 30 miles, because "the scientists who study all this say if we do this up to 10 miles, that is the safety zone."

Further out, even in a serious release of radioactive smoke, the dangerous particles are diluted in the shifting crosswinds of the immense airshed over the Phoenix metro area, Weaver says.

"We're fortunate here," he says, because only about 10,000 to 15,000 people live within that 10-mile zone, and it would be relatively easy to evacuate them.

In other parts of the United States, "millions" might be within the 10-mile zone of a nearby nuclear plant, Weaver says. Those people would have to shelter in place, initially, because a sudden evacuation would be impossible.

Presumably, an emergency at one of those older plants not using the newest technology is not as "unlikely," either.

After Palo Verde's second siren blast today, we'll go back to not thinking about nuclear accidents -- except for the one still going on in Japan.